Continuous counter-current organosolv processing of lignocellulosic feedstocks

ABSTRACT

A modular process for organosolv fractionation of lignocellulosic feedstocks into component parts and further processing of said component parts into at least fuel-grade ethanol and four classes of lignin derivatives. The modular process comprises a first processing module configured for physico-chemically digesting lignocellulosic feedstocks with an organic solvent thereby producing a cellulosic solids fraction and a liquid fraction, a second processing module configured for producing at least a fuel-grade ethanol and a first class of novel lignin derivatives from the cellulosic solids fraction, a third processing module configured for separating a second class and a third class of lignin derivatives from the liquid fraction and further processing the liquid fraction to produce a distillate and a stillage, a fourth processing module configured for separating a fourth class of lignin derivatives from the stillage and further processing the stillage to produce a sugar syrup.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a divisional application of U.S. patent applicationSer. No. 12/268,417 filed Nov. 10, 2008, which is a Continuation ofapplication Ser. No. 12/022,831 filed on Jan. 30, 2008, now U.S. Pat.No. 7,465,791, which is a Continuation of application Ser. No.12/016,932 filed on Jan. 18, 2008, which is a Continuation-in-part ofapplication Ser. No. 11/839,378 filed Aug. 15, 2007, and claims thebenefit of U.S. Provisional Application No. 60/941,220 filed May 31,2007.

FIELD OF THE INVENTION

This invention relates to fractionation of lignocellulosic feedstocksinto component parts. More particularly, this invention relates toprocesses, systems and equipment configurations for recyclableorganosolv fractionation of lignocellulosic material for continuouscontrollable and manipulable production and further processing oflignins, monosaccharides, oligosaccharides, polysaccharides and otherproducts derived therefrom.

BACKGROUND OF THE INVENTION

Industrial processes for production of cellulose-rich pulps fromharvested wood are well-known and typically involve the steps ofphysical disruption of wood into smaller pieces and particles followedby chemical digestion under elevated temperatures and pressures todissolve and separate the lignins from the constituent cellulosicfibrous biomass. After digestion has been completed, the solidscomprising the cellulosic fibrous pulps are separated from the spentdigestion liquids which commonly referred to as black liquors andtypically comprise organic solvents, solubilized lignins, solid andparticulate monosaccarides, oligosaccharides, polysaccharides and otherorganic compounds released from the wood during the chemical digestion.The cellulosic fibrous pulps are typically used for paper manufacturingwhile the black liquors are usually processed to remove the solublelignins after which, the organic solvents are recovered, purified andrecycled. The lignins and remaining stillage from the black liquors aretypically handled and disposed of as waste streams.

During the past two decades, those skilled in these arts have recognizedthat lignocellulosic materials including gymnosperm and angiospermsubstrates (i.e., wood) as well as field crop and other herbaceousfibrous biomass, waste paper and wood containing products and the like,can be potentially fractionated using biorefining processesincorporating organosolv digestion systems, into multiple usefulcomponent parts that can be separated and further processed intohigh-value products such as fuel ethanol, lignins, furfural, aceticacid, purified monosaccharide sugars among others (Pan et al., 2005,Biotechnol. Bioeng. 90: 473-481; Pan et al., 2006, Biotechnol Bioeng.94: 851-861; Berlin et al., 2007, Appl. Biochem. Biotechnol.136-140:267-280; Berlin et al., 2007, J. Chem. Technol Biotechnol. 82:767-774). Organosolv pulping processes and systems for lignocellulosicfeedstocks are well-known and are exemplified by the disclosures in U.S.Pat. Nos. 4,941,944; 5,730,837; 6,179,958; and 6,228,177. Although itappears that biorefining using organosolv systems has considerablepotential for large-scale fuel ethanol production, the currentlyavailable processes and systems are not yet economically feasiblebecause they require expensive pretreatment steps and currently produceonly low-value co-products (Pan et al., 2006, J. Agric. Food Chem. 54:5806-5813; Berlin et al., 2007, Appl. Biochem. Biotechnol.136-140:267-280; Berlin et al., 2007, J. Chem. Technol Biotechnol. 82:767-774).

SUMMARY OF THE INVENTION

The exemplary embodiments of the present invention relate to systems,processes and equipment configurations for receiving and controllablycommingling lignocellulosic feedstocks with counter-flowing organicsolvents while providing suitable temperature and pressure conditionsfor fractionating the lignocellulosic feedstocks into component partswhich are then subsequently separated. The separated component parts arefurther selectively, controllably and manipulably processed.

According to one exemplary embodiment of the present invention, there isprovided a modular processing system for receiving therein andfractionating a lignocellulosic feedstock into component parts,separating the component parts into at least a solids fraction and aliquids fraction, and then separately processing the solids and liquidsfractions to further produce useful products therefrom. Suitable modularprocessing systems of the present invention comprise at least:

-   -   a first module comprising a plurality of equipment configured        for: (a) receiving and processing lignocellulosic fibrous        feedstocks, then (b) commingling under controlled temperature        and pressure conditions the processed feedstocks with suitable        solvents configured for physico-chemically disrupting the        lignocellulosic feedstock into a solids fraction comprising        mostly cellulosic pulps and a liquid fraction comprising spent        solvents containing therein at least lignins, lignin-containing        compounds, monosaccharides, oligosaccharides and polysaccarides,        dissolved and suspended solids comprising hemicelluloses and        celluloses and other organic compounds, and (c) providing a        first output stream comprising the solids fraction and a second        output stream comprising the liquids fraction;    -   a second module comprising a plurality of equipment configured        for: (d) receiving and controllably adjusting the viscosity of        the solids fraction, (e) commingling the adjusted-viscosity        solids fraction with suitable enzymes selected for        saccharification of the cellulosic pulps into a liquid stream        comprising monosaccharides and/or oligosaccharides (f)        commingling the monosaccharides and/or oligosaccharides liquid        stream with suitable fermenting microorganisms for production of        an ethanol stream therefrom, (g) refining the ethanol to produce        at least a fuel grade ethanol stream and de-alcoholized solvent        stream, (h) further processing the de-alcoholized        solvent-stillage stream to precipitate and separate a first        lignin fraction therefrom, and (i) recycling the de-lignified        de-alcholized solvent stream for controllably adjusting the        viscosity of fresh solids fraction coming into the second module        from the first output stream of the first module;    -   a third module comprising a plurality of equipment configured        for (j) receiving the liquids fraction from the first module and        controllably intermixing a supply of water with the liquids        fraction thereby precipitating a second lignin fraction        therein, (k) separating the second lignin fraction from the        liquids fraction thereby producing a liquid filtrate, (l)        refining the liquid filtrate in a distillation tower thereby by        capturing at least firstly, a portion of the suitable solvents        commingled with the lignocellulosic feedstock in the first        module, secondly, a furfural fraction, and thirdly, a stillage        fraction, (m) controllably recharging the captured portion of        the suitable solvents with a portion of the fuel ethanol        produced in the second module; and    -   a fourth module comprising a plurality of equipment configured        for receiving the stillage fraction from the third module and        separating therefrom at least acetic acid condensate, sugar        syrups, a third lignin fraction, and a semi-solid/solid waste        material.

According to one aspect, the plurality of equipment in the first moduleis configured to continuously receive and convey therethrough in onedirection a lignocellulosic feedstock ending with the discharge of acellulosic solids fraction, while concurrently counterflowing a selectedsuitable solvent through the equipment in an opposite direction to theconveyance of the lignocellulosic feedstock ending in a discharge of aspent solvents liquid fraction.

According to another aspect, the plurality of equipment in the firstmodule is configured to receive a batch of a lignocellulosic feedstockand to continuously cycle therethrough a selected suitable solventtherethrough until a suitable solids fraction is produced from the batchof lignocellulosic feedstock.

According to yet another aspect, the plurality of equipment in thesecond module is configured to sequentially: (a) receive and reduce theviscosity of the cellulosic solids fraction discharged from the firstmodule, then (b) progressively saccharify the cellulosic solids intosuspended solids, dissolved solids, hemicelluloses, polysaccharides,oligosaccharides thereby producing a liquid stream primarily comprisingmonosaccharides, (c) ferment the liquid stream, (d) distill and refinethe fermentation beer to separate the beer into at least a fuel-gradeethanol and/or other fuel alcohols such as butanol, and a stillagestream, (e) delignify the stillage stream, and (f) recycle thedelignified stillage stream for reducing the viscosity of fresh incomingcellulosic solids fraction discharged from the first module.

According to a further aspect, the plurality of equipment in the secondmodule may be optionally configured to sequentially: (a) receive andreduce the viscosity of the cellulosic solids fraction discharged fromthe first module, then (b) concurrently saccharify the cellulosic solidsinto monosaccharides while fermenting the monosaccharides in the samevessel, (c) distill and refine the fermentation beer to separate thebeer into at least a fuel-grade ethanol and a stillage stream, (d)de-lignify the stillage stream, and (f) recycle the de-lignifiedstillage stream for reducing the viscosity of fresh incoming cellulosicsolids fraction discharged from the first module.

According to another aspect, the modular processing system of thepresent system may be additionally provided with a fifth modulecomprising an anaerobic digestion system provided with a plurality ofequipment configured for receiving the semi-solid/solid waste materialfrom the fourth module, then liquifying and gasifying the waste materialfor the production of methane, carbon dioxide, and water.

According to another exemplary embodiment of the present invention,there is provided processes for fractionating a lignocellulosicfeedstock into component parts. First, foreign materials exemplified bygravel and metal are separated using suitable means, from the incominglignocellulosic material. An exemplary separating means is screening. Ifso desired, the screened lignocellulosic feedstock may be furtherscreened to remove fines and over-size materials. Second, the screenedlignocellulosic feedstock are controllably heated for example bysteaming after which, the heated lignocellulosic feedstock is de-wateredand then pressurized. Third, the heated and de-watered lignocellulosicfeedstock is commingled and then impregnated with a suitable organicsolvent. Fourth, the commingled lignocellulosic feedstock and organicsolvent are controllably cooked within a controllably pressurized andtemperature-controlled system for a selected period of time. During thecooking process, lignins and lignin-containing compounds containedwithin the commingled and impregnated lignocellulosic feedstock will bedissolved into the organic solvent resulting in the cellulosic fibrousmaterials adhered thereto and therewith to disassociate and to separatefrom each other. The cooking process will also release monosaccharides,oligosaccharides and polysaccarides and other organic compounds forexample acetic acid, in solute and particulate forms, from thelignocellulosic materials into the organic solvents. Those skilled inthese arts refer to such organic solvents containing therein lignins,lignin-containing compounds, monosaccharides, oligosaccharides andpolysaccarides and other organic compounds, as “black liquors” or “spentliquors”.

According to one aspect, controllably counter-flowing the organicsolvent against the incoming lignocellulosic feedstock during thecooking causes turbulence that facilitates and speeds the dissolutionand disassociation of the lignins and lignin-containing components fromthe lignocellulosic feedstock. However, it is within the scope of thisinvention to alternatively provide turbulence during the cooking processwith a controllable flow of organic solvent directed in the samedirection as the flow of lignocellulosic feedstock, i.e., a concurrentflow, thereby controllably intermixing the solvent and lignocellulosicfeedstock together. It is also within the scope of this invention tocontrollably partially remove the organic solvent during the cookingprocess and to replace it with fresh organic solvent.

According to another aspect, the lignocellulosic feedstock may compriseat least one of physically disrupted angiosperm, gymnosperm, field cropfibrous biomass segments exemplified by chips, saw dust, chunks, shredsand the like. It is within the scope of this invention to providemixtures of physically disrupted angiosperm, gymnosperm, field cropfibrous biomass segments.

According to yet another aspect, the lignocellulosic feedstock maycomprise at least one of waste paper, wood scraps, comminuted woodmaterials, wood composites and the like. It is within the scope of thisinvention to intermix lignocellulosic fibrous biomass materials with oneor more of waste paper, wood scraps, comminuted wood materials, woodcomposites and the like.

According to a further aspect, the liquor to wood ratio, operatingtemperature, solvent concentration and reaction time may be controllablyand selectively adjusted to produce pulps and/or lignins havingselectable target physico-chemical properties and characteristics.

According to another exemplary embodiment of the present invention,there are provided processes and systems for separating thedisassociated cellulosic fibers i.e., pulp, from the black liquors, andfor further and separately processing the pulp and the black liquors.The separation of pulp and black liquors may be done while the materialsare still pressurized from the cooking process or alternatively,pressure may be reduced to about ambient pressure after which the pulpand black liquors are separated.

According to one aspect, the cellulosic fibrous pulp is recoverable foruse in paper making and other such processes.

According to another aspect, there are provided processes and systemsfor further selectively and controllably processing the cellulosic pulpsproduced as disclosed herein. The pH and/or the consistency of therecovered pulp may be adjusted as suitable to facilitate the hydrolysisof celluloses to monosaccharides, i.e., glucose moieties in hydrolysatesolutions. Exemplary suitable hydrolysis means include enzymatic,microbial, chemical hydrolysis and combinations thereof.

According to yet another aspect, there are provided processes andsystems for producing ethanol from the monosaccarides hydrolyzed fromthe cellulosic fibrous pulp, by fermentation of the hydrolysatesolutions. It is within the scope of this invention to controllablyprovide inocula comprising one or more selected strains of Saccharomycesspp. to facilitate and enhance the rates of fermentation and/orfermentation efficiencies and/or fermentation yields.

According to a further aspect, there are provided processes and systemsfor concurrently saccharifying and fermenting the cellulosic pulpsproduced as disclosed herein. It is within the scope of the presentinvention to controllably hydrolyze the cellulosic fibrous pulps intomonosaccharides by providing suitable hydrolysis means exemplified byenzymatic, microbial, chemical hydrolysis and combinations thereof,while concurrently and controllably fermenting the monosaccharidemoieties produced therein. It is within the scope of this invention tocontrollably provide inocula comprising one or more selected strains ofSaccharomyces spp. to facilitate and enhance the rates of concurrentfermentation and/or fermentation efficiencies and/or fermentationyields.

According to a further aspect, there are provided processes and systemsfor further processing the ethanol produced from the fermentation of thehydrolysate solutions. Exemplary processes include concentrating andpurifying the ethanol by distillation, and de-watering or dehydration bypassing the ethanol through at least one molecular sieve.

According to a further exemplary embodiment of the present invention,there are provided processes and systems for recovering lignins andlignin-containing compounds from the black liquors. An exemplary processcomprises cooling the black liquor immediately after separation from thecellulosic fibrous pulp, in a plurality of stages wherein each stage,heat is recovered with suitable heat-exchange devices and organicsolvent is recovered using suitable solvent recovery apparatus asexemplified by evaporation and cooling devices. The stillage, i.e., thecooled black liquors from which at least some organic solvent has beenrecovered, are then further cooled, pH adjusted (e.g. increasingacidity) and then rapidly diluted with water to precipitate lignins andlignin-containing compounds from the stillage. The precipitated ligninsare subsequently washed at least once and then dried.

According to one aspect, the de-lignified stillage is processed througha distillation tower to evaporate remaining organic solvent, and toconcurrently separate and concentrate furfural. The remaining stillageis removed from the bottom of the distillation tower. It is within thescope of the present invention to optionally divert at least a portionof the de-lignified stillage from the distillation tower input streaminto the ethanol production stream for producing ethanol therefrom.Alternatively or optionally, at least a portion of the remainingstillage removed from the bottom of the distillation tower may bediverted into the ethanol production stream for producing ethanoltherefrom.

According to another aspect, the stillage recovered form the bottom ofthe solvent recovery column, is further processed by: (a) decanting torecover complex organic extractives as exemplified by phytosterols, oilsand the like, and then (b) evaporating the decanted stillage to produce(c) a stillage evaporate/condensate comprising acetic acid, and (d) astillage syrup containing therein dissolved monosaccharides. Thestillage syrup may be decanted to recover (e) novel previously unknownlow molecular weight lignins. The decanted stillage syrup may beoptionally evaporated to recover dissolved sugars.

It is within the scope of this invention to further process therecovered organic solvent by purification and concentration steps tomake the recovered organic solvent useful for recycling back intocontinuous incoming lignocellulosic feedstock.

According to one aspect, an organic solvent is intermixed and commingledwith the lignocellulosic feedstock for a selected period of time topre-treat the lignocellulosic feedstock prior to commingling andimpregnation with the counter-flowing (or alternatively, concurrentlyflowing) organic solvent.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention will be described in conjunction with reference tothe following drawings in which:

FIG. 1 is a schematic flowchart of an exemplary embodiment of thepresent invention of a modular continuous counter-flow system forprocessing a lignocellulosic feedstock;

FIG. 2 is a schematic flowchart of the system from FIG. 1 additionallyprovided with a device for optionally diverting the sugar output streamto (a) the fuel ethanol production module, and (b) an anaerobicdigestion module;

FIG. 3 is schematic flowchart showing an alternative configuration ofthe fuel ethanol production module for concurrent saccharification andfermentation processes within a single vessel;

FIG. 4 is a schematic flowchart of an exemplary anaerobic digestionmodule suitable for cooperating with the modular continuous counter-flowsystem of the present invention for processing a lignocellulosicfeedstock;

FIG. 5 is a schematic flowchart of a continuous counter-flow processingsystem of the process re-configured into a batch through-put system;

FIG. 6 is a schematic flowchart showing an alternative configuration forthe batch throughput system shown in FIG. 5;

FIG. 7 shows plots illustrating the simultaneous saccharification andfermentation (SSF) of organosolv-pretreated aspen (Populus tremuloides)chips: (a) % theoretical yield of ethanol produced from the resultantaspen pulps vs. time, and (b) the ethanol concentration in beers vs.time, produced during SSF of the aspen pulps;

FIG. 8 shows plots illustrating the SSF of organosolv-pretreated BritishColumbian beetle-killed lodgepole pine (Pinus contorta) chips: (a) %theoretical yield of ethanol produced from the resultant beetle-killedlodgepole pine pulps vs. time, and (b) the ethanol concentration inbeers vs. time, produced during SSF of the resultant beetle-killedlodgepole pine pulps; and

FIG. 9 shows plots illustrating the simultaneous saccharification andfermentation (SSF) of organosolv-pretreated wheat straw and switchgrasslignocellulosic feedstocks: (a) % theoretical yield of ethanol producedfrom the resultant cellulosic pulps vs. time, and (b) the ethanolconcentration in beers vs. time, produced during SSF of the cellulosicpulps.

DETAILED DESCRIPTION OF THE INVENTION

Exemplary embodiments of the present invention relate to systems,processes and equipment configurations for receiving and controllablycommingling lignocellulosic feedstocks with counter-flowing organicsolvents, thereby fractionating the lignocellulosic feedstocks intocomponent parts which are then subsequently separated. The separatedcomponent parts are further selectively, controllably and manipulablyprocessed. The exemplary embodiments of the present invention areparticularly suitable for separating out from lignocellulosic feedstocksat least four structurally distinct classes of lignin component partswith each class comprising multiple derivative lignin compounds, whileconcurrently providing processes for converting other component partsinto at least fuel-grade ethanol, furfurals, acetic acid, andmonosaccharide and/or oligosaccharides sugar streams.

An exemplary modular processing system of the present invention is shownin FIG. 1 and generally comprises four modules A-D wherein the firstmodule A is configured for receiving and processing lignocellulosicfeedstocks into a solids fraction and a liquids fraction, the secondmodule B is configured for receiving the solids fraction discharged fromthe first module A and producing therefrom at least a fuel ethanoloutput stream 100 and a first class of lignin derivatives 120 referredto hereafter as a medium molecular weight lignin (i.e., MMW lignin), thethird module C is configured for receiving the liquid fraction from thefirst module A and separating out at least a second class of ligninderivatives 170 referred to hereafter as high molecular weight lignins(i.e., HMW lignins), after which the filtrate is separated into at leastrecyclable distilled solvent, furfurals 190, and a stillage, and thefourth module D is configured for receiving and separating the stillagefrom the third module C into at least acetic acid 210, a third class oflignin derivatives 230 referred to hereafter as low molecular weightlignins (i.e., LMW lignins), a sugar syrup stream 247 from which isdecanted and separated a fourth class of lignin derivatives 245 referredto hereafter as very-low molecular weight lignins (i.e., VLMW lignins),and a semi-solid/solid waste material 226.

The first module A as exemplified in FIG. 1 is provided with a bin 10configured for receiving and temporarily storing lignocellulosicfeedstocks while continually discharging the feedstock into a conveyancesystem provided with a separating device 20 configured for removingpebbles, gravel, metals and other debris. A suitable separating deviceis a screening apparatus. The separating device 20 may be optionallyconfigured for sizing the lignocellulosic feedstock into desiredfractions. The processed lignocellulosic feedstock is then conveyed witha first auger feeder 30 into a first end of a digestion/extractionvessel 40 and then towards the second end of the digestion/extractionvessel 40. The vessel 40 is provided with an inlet approximate thesecond end for receiving a pressurized stream of a suitable heateddigestion/extraction solvent which then counterflows against themovement of the lignocellulosic feedstock through the vessel 40 therebyproviding turbulence and commingling of the solvent with the feedstock.Alternatively, the inlet for receiving the pressurized stream of heateddigestion/extraction solvent may be provided about the first end of thedigestion/extraction vessel 40 or further alternatively, interposed thefirst and second ends of the digestion/extraction vessel 40. It issuitable to use organic solvents for the processes of the presentinvention. Exemplary suitable organic solvents include methanol,ethanol, propanol, butanol, acetone, and the like. If so desired, theorganic solvents may be additionally controllably acidified with aninorganic or organic acid. If so desired, the pH of the organic solventsmay be additionally controllably manipulated with an inorganic ororganic base. The vessel 40 is controllably pressurized and temperaturecontrolled to enable manipulation of pressure and temperature so thattarget cooking conditions are provided while the solvent is comminglingwith the feedstock. Exemplary cooking conditions include pressures inthe range of about 15-30 bar (g), temperatures in the range of about120-350° C., and pHs in the range of about 1.5-5.5. During the cookingprocess, lignins and lignin-containing compounds contained within thecommingled and impregnated lignocellulosic feedstock will be dissolvedinto the organic solvent resulting in the cellulosic fibrous materialspreviously adhered thereto and therewith to disassociate and to separatefrom each other. Those skilled in these arts will understand that inaddition to the dissolution of lignins and lignin-containing polymers,the cooking process will release monosaccharides, oligosaccharides andpolysaccharides and other organic compounds for example acetic acid,furfural, 5-hydroxymethyl furfural (5-HMF), other organic acids such asformic and levulinic acids in solute and particulate forms, from thelignocellulosic materials into the organic solvents. Those skilled inthese arts refer to such organic solvents containing the lignins,lignin-containing compounds, monosaccharides, oligosaccharides,polysaccharides, hemicelluloses and other organic compounds extractedfrom the lignocellulosic feedstock, as “black liquors” or “spentliquors”. The disassociated cellulosic fibrous materials released fromthe feedstock are conveyed to the second end of the vessel 40 where theyare discharged via a second auger feeder 50 which compresses thecellulosic fibrous materials into a solids fraction, i.e., a pulp whichis then conveyed to the second module B. The black liquors aredischarged as a liquid fraction from about the first end of thedigestion/extraction vessel 40 into a pipeline 47 for conveyance to thethird module C.

The second module B is provided with a mixing vessel 60 wherein theviscosity of solids fraction, i.e., pulp discharged from the firstmodule A is controllably reduced to a selected target viscosity, bycommingling with a recovered recycled solvent stream delivered by apipeline 130 from a down-stream component of module B. The reducedviscosity pulp is then transferred to a digestion vessel 70 where asuitable enzymatic preparation is intermixed and commingled with thepulp for progressively breaking down the cellulosic fibers, suspendedsolids and dissolved solids into hemicelluoses, polysaccharides,oligosaccharides and monosaccharides. A liquid stream comprising thesedigestion products is transferred from the digestion vessel 70 to afermentation vessel 80 and is commingled with a suitable microbialinocula selected for fermentation of hexose and pentose monosaccharidesin the liquid stream thereby producing a fermentation beer comprising atleast a short-chain alcohol exemplified by ethanol, residual sedimentsand lees. The fermentation beer is transferred to a first distillationtower 90 for refining by volatilizing then distilling and separatelycollecting from the top of the distillation tower 90 at least afuel-grade ethanol which is transferred and stored in a suitable holdingcontainer 100. The remaining liquid stillage is removed from the bottomof distillation tower 90 to equipment 110 configured to precipitate andseparate MMW lignins which are then collected and stored in a suitablevessel 120 for further processing and/or shipment. It is within thescope of the present invention to heat the stillage and flash it withcold water to facilitate precipitation of the MMW lignins. Thede-lignified stillage may then be controllably recycled from equipment110 via pipeline 130 to the mixing vessel 60 for reducing the viscosityof fresh incoming pulp from the first module A.

Suitable enzyme preparations for addition to digestion vessel 70 forprogressively breaking down cellulosic fibers into hemicelluloses,polysaccharides, oligosaccharides and monosaccharides may comprise oneor more of enzymes exemplified by endo-β-1,4-glucanases,cellobiohydrolases, β-glucosidases, β-xylosidases, xylanases,α-amylases, β-amylases, pullulases, esterases, other hemicellulases andcellulases and the like. Suitable microbial inocula for fermentingpentose and/or hexose monosaccharides in fermentation vessel 80 maycomprise one or more suitable strains selected from yeast species,fungal species and bacterial species. Suitable yeasts are exemplified bySaccharomyces spp. and Pichia spp. Suitable Saccharomyces spp areexemplified by S. cerevisiae such as strains Sc Y-1528, Tembec-1 and thelike. Suitable fungal species are exemplified by Aspergillus spp. andTrichoderma spp. Suitable bacteria are exemplified by Escherichia coli,Zymomonas spp., Clostridium spp., and Corynebacterium spp. among others,naturally occurring and genetically modified. It is within the scope ofthe present invention to provide an inoculum comprising a single strain,or alternatively a plurality of strains from a single type of organism,or further alternatively, mixtures of strains comprising strains frommultiple species and microbial types (i.e. yeasts, fungi and bacteria).

The black liquors discharged as a liquid fraction from thedigestion/extraction vessel 40 of third module A, are processed inmodule C to recover at least a portion of the digestion/extractionsolvent comprising the black liquors, and to separate useful componentsextracted from the lignocellulosic feedstocks as will be described inmore detail below. The black liquors are transferred by pipeline 47 intoa heating tower 140 wherein they are first heated and then rapidly mixed(i.e., “flashed”) and commingled with a supply of cold water therebyprecipitating HMW lignins from the black liquor. The precipitated HMWlignins are separated from the water-diluted black liquor by a suitablesolids-liquids separation equipment 150 as exemplified by filteringapparatus, hydrocyclone separators, centrifuges and other suchequipment. The separated HMW lignins are transferred to a lignin drier160 for controlled removal of excess moisture, after which the dried HMWlignins are transferred to a storage bin 170 for packaging and shipping.

The de-lignified filtrate fraction is transferred from the separationequipment 150 to a second distillation tower 180 for vaporizing,distilling and recovering therefrom a short-chain alcohol exemplified byethanol. The recovered short-chain alcohol is transferred to adigestion/extraction solvent holding tank 250 where it may, if sodesired, be commingled with a portion of fuel-grade ethanol produced inmodule B and drawn from pipeline 95, to controllably adjust theconcentration and composition of the digestion/extraction solvent priorto supplying the digestion/extraction solvent via pipeline 41 to thedigestion/extraction vessel 40 of module A. It is within the scope ofthe present invention to recover furfurals from the de-lignifiedfiltrate fraction concurrent with the vaporization and distillationprocesses within the second distillation tower, and transfer therecovered furfurals to a storage tank 190. An exemplary suitable processfor recovering furfurals is to acidify the heated de-lignified filtratethereby condensing furfurals therefrom. It is within the scope of thepresent invention to supply suitable liquid bases or acids tocontrollably adjust the pH of the de-lignified filtrate fraction.Suitable liquid bases are exemplified by sodium hydroxide. Suitableacids are exemplified by sulfuric acid.

The stillage from the second distillation tower is transferred to thefourth module D for further processing and separation of useful productstherefrom. The hot stillage is transferred into a cooling tower 200configured to collect a condensate comprising acetic acid which is thentransferred to a suitable holding vessel 210. The de-acidified stillageis then transferred to a stillage processing vessel 220 configured forheating the stillage followed by flashing with cold water therebyprecipitating LMW lignins which are then separated from a sugar syrupstream, and a semi-solid/solid waste material discharged into a wastedisposal bin 226. The LMW lignins are transferred to a suitable holdingcontainer 230 for further processing and/or shipment. The sugar syrupstream, typically comprising at least one of xylose, arabinose, glucose,mannose and galactose, is passed through a decanter 240 which separatesVLMW lignins from the sugar syrup stream thereby purifying the sugarsyrup stream which is transferred to a suitable holding tank 247 priorto further processing and/or shipping, The VLMW lignins are transferredto a suitable holding tank 245 prior to further processing and/orshipping.

FIG. 2 illustrates exemplary modifications that are suitable for themodular lignocellulosic feedstock processing system of the presentinvention.

One exemplary embodiment includes provision of a pre-treatment vessel 25for receiving therein processed lignocellulosic feedstock from theseparating device 20 for pre-treatment prior to digestion and extractionby commingling and saturation with a heated digestion/extraction solventfor a suitable period of time. A suitable supply of digestion/extractionsolvent may be diverted from pipeline 41 by a valve 42 and delivered tothe pre-treatment vessel 25 by pipeline 43. Excess digestion/extractionsolvent is squeezed from the processed and pre-treated lignocellulosicfeedstock by the mechanical pressures applied by the first auger feeder30 during transfer of the feedstock into the digestion/extraction vessel40. The extracted digestion/extraction solvent is recyclable viapipeline 32 back to the pre-treatment vessel 25 for commingling withincoming processed lignocellulosic feedstock and fresh incomingdigestion/extraction solvent delivered by pipeline 43. Suchpre-treatment of the processed lignocellulosic feedstock prior to itsdelivery to the digestion/extraction vessel 40 will facilitate the rapidabsorption of digestion/extraction solvent during the commingling andcooking process and expedite the digestion of the lignocellulosicfeedstock and extraction of components therefrom.

Another exemplary embodiment illustrated in FIG. 2 provides a seconddiverter valve 260 interposed the sugar syrup stream discharged from thedecanter 240 in module D. In addition to directing the sugar stream tothe sugar stream holding tank 240, the second diverter valve 260 isconfigured for controllably diverting a portion of the liquid sugarstream into a pipeline 270 for delivery into the fermentation tank 80 inmodule B. Such delivery of a portion of the liquid sugar stream frommodule D will enhance and increase the rate of fermentation in tank 80and furthermore, will increase the volume of fuel-grade ethanol producedfrom the lignocellulosic feedstock delivered to module A.

Another exemplary embodiment illustrated in FIG. 2 provides an optionalfifth module E comprising an anaerobic digestion system configured toreceive semi-solid/solid wastes from the stillage processing vessel 220and optionally configured for receiving a portion of the sugar syrupstream discharged from the stillage processing vessel 220. An exemplaryanaerobic digestion system comprising module E of the present inventionis illustrated in FIG. 3 and generally comprises a sludge tank 310, avessel 320 configured for containing therein biological acidificationprocesses (referred to hereinafter as an acidification vessel), a vessel330 configured for containing therein biological acetogenesis processes(referred to hereinafter as an acetogenesis vessel), and a vessel 340configured for containing therein biological processes for conversion ofacetic acid into biogas (referred to hereinafter as a biogas vessel).The semi-solid/solid waste materials produced in the stillage processingvessel 220 of module C are transferred by a conveyance apparatus 225 tothe sludge tank 310 wherein anaerobic conditions and suitablepopulations of facultative anaerobic microorganisms are maintained.Enzymes produced by the facultative microorganisms hydrolyze the complexorganic molecules comprising the semi-solid/solid waste materials intosoluble monomers such as monosaccharides, amino acids and fatty acids.It is within the scope of the present invention to provide if so desiredinocula compositions for intermixing and commingling with thesemi-solid/solid wastes in the sludge tank 310 to expedite thehydrolysis processes occurring therein. Suitable hydrolyzing inoculacompositions are provided with at least one Enterobacter sp. A liquidstream containing therein the hydrolyzed soluble monomers is transferredinto the acidification vessel 320 wherein anaerobic conditions and apopulation of acidogenic bacteria are maintained. The monosaccharides,amino acids and fatty acids contained in the liquid stream received bythe acidification vessel 320 are converted into volatile acids by theacidogenic bacteria. It is within the scope of the present invention toprovide if so desired acidification inocula compositions configured forfacilitating and expediting the production of solubilized volatile fattyacids in the acidification tank 320. Suitable acidification inoculacompositions are provided with at least one of Bacillus sp.,Lactobacillus sp. and Streptococcus sp. A liquid stream containingtherein the solubilized volatile fatty acids is transferred into theacetogenesis vessel 330 wherein anaerobic conditions and a population ofacetogenic bacteria are maintained. The volatile fatty acids areconverted by the acetogenic bacteria into acetic acid, carbon dioxide,and hydrogen. It is within the scope of the present invention to provideif so desired inocula compositions configured for facilitating andexpediting the production of acetic acid from the volatile fatty acidsdelivered in the liquid stream into in the acetogenesis vessel 330.Suitable acetification inocula compositions are provided with at leastone of Acetobacter sp., Gluconobacter sp., and Clostridium sp. Theacetic acid, carbon dioxide, and hydrogen are then transferred from theacetogenesis vessel 330 into the biogas vessel 340 wherein the aceticacid is converted into methane, carbon dioxide and water. Thecomposition of the biogas produced in the biogas vessel 330 of module Ewill vary somewhat with the chemical composition of the lignocellulosicfeedstock delivered to module A, but will typically comprise primarilymethane and secondarily CO₂, and trace amounts of nitrogen gas,hydrogen, oxygen and hydrogen sulfide. It is within the scope of thepresent invention to provide if so desired methanogenic inoculacompositions configured for facilitating and expediting the conversionof acetic acid to biogas. Suitable methanogenic inocula compositions areprovided with at least one of bacteria are from the Methanobacteria sp.,Methanococci sp., and Methanopyri sp. The biogas can be fed directlyinto a power generation system as exemplified by a gas-fired combustionturbine. Combustion of biogas converts the energy stored in the bonds ofthe molecules of the methane contained in the biogas into mechanicalenergy as it spins a turbine. The mechanical energy produced by biogascombustion, for example, in an engine or micro-turbine may spin aturbine that produces a stream of electrons or electricity. In addition,waste heat from these engines can provide heating for the facility'sinfrastructure and/or for steam and/or for hot water for use as desiredin the other modules of the present invention.

However, a problem with anaerobic digestion of semi-solid/solid wastematerials is that the first step in the process, i.e., the hydrolysis ofcomplex organic molecules comprising the semi-solid/solid wastematerials into a liquid stream containing soluble monomers such asmonosaccharides, amino acids and fatty acids, is typically lengthy andvariable, while the subsequent steps, i.e., acidification,acetification, and biogas production proceed relatively quickly incomparison to the first step. Consequently, such lengthy and variablehydrolysis in the first step of anaerobic may result in insufficientamounts of biogas production relative to the facility's requirements forpower production and/or steam and/or hot water. Accordingly, anotherembodiment of the present invention, as illustrated in FIGS. 2 and 3,controllably provides a portion of the sugar syrup stream dischargedfrom the stillage processing vessel 220 of module D, to theacidification tank 320 of module E to supplement the supply of solublemonosaccharides hydrolyzed from semi-solid/solid materials delivered tothe sludge tank 310. Thus, the amount of biogas produced by module E ofthe present invention can be precisely manipulated and modulated byproviding a second diverter 260 interposed the sugar syrup dischargeline from stillage processing vessel 220, to controllably divert aportion of the sugar syrup into pipeline 275 for transfer to theacidification vessel 320.

Another exemplary embodiment of the present invention is illustrated inFIG. 4 and provides an optional vessel 280 for module B, wherein vessel280 is configured for receiving the reduced viscosity pulp from mixingvessel 60 (FIG. 2) and for concurrent i.e., co-saccharification andco-fermentation therein of the reduced-viscosity solids fractions. Thoseskilled in these arts will understand that such co-saccharification andco-fermentation processes are commonly referred to as “simultaneoussaccharification and fermentation” (SSF) processes, and that vessel 280(referred to hereinafter as a SSF vessel) can replace digestion vessel70 and fermentation vessel 80 from FIG. 2. It is suitable to provide asupplementary stream of sugar syrup into the SSF vessel 280 via pipeline270 from the second diverter valve 260 (FIGS. 2 and 4) to controllablyenhance and increase the rate of fermentation in the SSF vessel 280.

Another exemplary embodiment of the present invention is illustrated inFIG. 5 and provides an alternative first module AA, for communicationand cooperation with modules B and C, wherein the alternative firstmodule AA (FIG. 5) is configured for receiving, processing anddigestion/extraction of batches of a lignocellulosic feedstock, ascompared to module A which is configured for continuous inflow,processing and digestion/extraction of a lignocellulosic feedstock (FIG.1). As shown in FIG. 5, one exemplary embodiment for batchdigestion/extraction of a lignocellulosic feedstock comprises a batchdigestion/extraction vessel 400 interconnected and communicating with adigestion/extraction solvent re-circulating tank 410 and a solvent pump420. A batch of lignocellulosic feedstock is loaded into a receiving bin430 from where it is controllably discharged into a conveyance systemprovided with a screening device 440 configured for removing pebbles,gravel, metals and other debris. The screening device 440 may beoptionally configured for sizing the lignocellulosic feedstock intodesired fractions. The processed lignocellulosic feedstock is thenconveyed with a third auger feeder 450 into a first end of the batchdigestion/extraction vessel 400. The digestion/extraction solventre-circulating tank 410 is configured to receive a suitabledigestion/extraction solvent from the digestion/extraction solventholding tank 250 of module B via pipeline 41. The digestion/extractionsolvent is pumped via solvent pump 420 into the batchdigestion/extraction vessel 400 wherein it controllably commingled,intermixed and circulated through the batch of lignocellulosic feedstockcontained therein. The batch digestion/extraction vessel 400 iscontrollably pressurized and temperature controlled to enablemanipulation of pressure and temperature so that target cookingconditions are provided while the solvent is commingling and intermixingwith the feedstock. Exemplary cooking conditions include pressures inthe range of about 15-30 bar(g), temperatures in the range of about120°-350° C., and pHs in the range of about 1.5-5.5. During the cookingprocess, lignins and lignin-containing compounds contained within thecommingled and impregnated lignocellulosic feedstock will be dissolvedinto the organic solvent resulting in the cellulosic fibrous materialsadhered thereto and therewith to disassociate and to separate from eachother. Those skilled in these arts will understand that in addition tothe dissolution of lignins and lignin-containing polymers, the cookingprocess will release monosaccharides, oligosaccharides andpolysaccharides and other organic compounds for example acetic acid, insolute and particulate forms, from the lignocellulosic materials intothe organic solvents. It is suitable to discharge thedigestion/extraction solvent from the batch digestion/extraction vessel400 through pipeline 460 during the cooking process for transfer viapipeline 460 back to the digestion/extraction solvent re-circulatingtank 410 for re-circulation by the solvent pump 420 back into the batchdigestion/extraction vessel 400 until the lignocellulosic feedstock issuitable digested and extracted into a solids fraction comprising aviscous pulp material comprising dissociated cellulosic fibers, and aliquids fraction, i.e., black liquor, comprising solubilized lignins andlignin-containing polymers, hemicelluloses, polysaccharides,oligosaccharides, monosaccharides and other organic compounds in soluteand particulate forms, from the lignocellulosic materials in the spentorganic solvents. It is within the scope of the present invention towithdraw a portion of the re-circulating digestion/extraction solventfrom the solvent re-circulating tank 410 via pipeline 465 for transferto the heating tower 140 in module C, and to replace the withdrawnportion of re-circulating digestion/extraction solvent with freshdigestion/extraction solvent from the digestion/extraction solventholding tank 250 of module B via pipeline 41, thereby expediting thedigestion/extraction processes within the batch digestion/extractionvessel 400. After digestion/extraction of the lignocellulosic feedstockhas been completed, the solids fraction comprising cellulosic fibre pulpis discharged from the batch digestion/extraction vessel 400 andconveyed to the mixing vessel 60 in module B wherein the viscosity ofthe solids fraction, i.e., pulp discharged from the first module AA, iscontrollably reduced to a selected target viscosity by commingling andintermixing with de-lignified stillage delivered via pipeline 130 thenbe controllably recycled from de-lignification equipment 110 of module Bafter which the reduced-viscosity pulp is further processed bysaccharification, fermentation and refining as previously described. Theblack liquor is transferred from the digestion/extraction solventre-circulating tank 410 via pipeline 465 to the heating tower 140 inmodule C for precipitating lignin therefrom and further processing aspreviously described.

A suitable exemplary modification of the batch digestion/extractionmodule component of the present invention is illustrated in FIG. 6,wherein a pre-treatment vessel 445 is provided for receiving thereinprocessed lignocellulosic feedstock from the screening device 440 forpre-treatment prior to conveyance to the batch digestion/extractionvessel 400, by commingling and saturation with a digestion/extractionsolvent for a suitable period of time. A suitable supply ofdigestion/extraction solvent may be diverted from pipeline 41 by a valve42 (shown in FIG. 2) and delivered to the pre-treatment vessel 445 bypipeline 43. Excess digestion/extraction solvent is squeezed from theprocessed and pre-treated lignocellulosic feedstock by the mechanicalpressures applied by the third auger feeder 450 during transfer of thefeedstock into the batch digestion/extraction vessel 400. The extracteddigestion/extraction solvent is recyclable via pipeline 455 back to thepre-treatment vessel 445 for commingling with incoming processedlignocellulosic feedstock and fresh incoming digestion/extractionsolvent delivered by pipeline 43. Such pre-treatment of the processedlignocellulosic feedstock prior to its delivery to the batchdigestion/extraction vessel 400 will facilitate the rapid absorption ofdigestion/extraction solvent during the commingling and cooking processand expedite the digestion of the lignocellulosic feedstock andextraction of components therefrom.

The systems, methods and processes for fractionating lignocellulosicfeedstocks into component parts which are then subsequently separatedare described in more detail in the following examples with a selectedhardwood and a selected softwood species. The following examples areintended to be exemplary of the invention and are not intended to belimiting.

Example 1

Representative samples of whole logs of British Columbian aspen (Populustremuloides) (˜125 years old) were collected. After harvesting, logswere debarked, split, chipped, and milled to a chip size ofapproximately ≦10 mm×10 mm×3 mm. Chips were stored at room temperature(moisture content at equilibrium was ˜10%). The aspen chips wereorganosolv-pretreated in aqueous ethanol (50% w/w ethanol) with noaddition of exogenous acid or base, in a 2-L Parr® reactor (Parr is aregistered trademark of the Parr Instrument Company, Moline, Ill., USA).Duplicate 200 g (ODW) samples of the aspen chips, designated as ASP1,were cooked at 195° C. for 60 min. The liquor:wood ratio was 5:1weight-based. After cooking, the reactor was cooled to room temperature.Solids and the spent liquor were then separated by filtration. Solidswere intensively washed with a hot ethanol solution (70° C.) followed bya tap water wash step. The moisture content of the washed pulp wasreduced to about 40% with the help of a hydraulic press (alternatively ascrew press can be used). The washed pulp was homogenized and stored ina fridge at 4° C. The chemical composition (hexose, pentose, lignincontent) of washed and unwashed pulps was determined according to amodified Klason lignin method derived from the Technical Association ofPulp and Paper Industry (TAPPI) standard method T222 om-88 (TAPPImethods in CD-ROM, 2004, TAPPI Press). Liquids were analyzed forcarbohydrate degradation products (furfural, 5-hydromethylfurfural),acids, and oligo- and monosaccharides according to standard proceduresestablished by the National Renewable Energy Laboratory (NREL, Golden,Colo., USA). The resulting data were used to calculate overall ligninand carbohydrate recoveries and process mass balance. The carbohydratecomposition and overall carbohydrate recoveries from the raw andpretreated aspen chips are shown in Table 1. 222.2 g (oven-dried weight,odw) of ASP1 pulp were recovered after batch organosolv processing of400 g of aspen wood chips (55.6% pulp yield) containing mainlyfermentable-into-ethanol carbohydrates. Pentoses and hexoses werepartially degraded resulting in 0.71 g Kg⁻¹ of furfural and 0.06 g Kg⁻¹of 5-HMF, respectively. The different classes of lignins recovered fromthe pulp and liquors are shown in Table 2.

TABLE 1 Carbohydrate content of raw and pretreated aspen chips (ASP1pretreatment conditions) and overall carbohydrate recovery RawPretreated Feedstock Raw Feedstock Output Carbohydrates Recovery chipsInput Pulp Liquor Total Soluble Insoluble Total Component (%) (g) (g)(g) (g) (%) (%) (%) Arabinan 0.44 1.75 0.04 0.17 0.21 9.69 2.53 12.23Galactan 0.43 1.71 0.16 0.26 0.42 15.16 9.07 24.23 Glucan 48.76 195.03185.40 0.32 185.72 0.16 95.06 95.23 Xylan 16.44 65.75 17.60 8.70 26.3013.23 26.77 40.00 Mannan 1.48 5.92 4.62 0 4.62 0 78.02 78.02 Total:67.55 270.16 207.82 9.45 217.27

TABLE 2 Lignin input in raw aspen chips and lignin fractions recoveredafter organosolv pretreatment (ASP1 pretreatment conditions) RawPretreated Pretreated Feedstock Feedstock Feedstock Input Solids OutputLiquids Output Component (g) (odw, g) (odw, g) Raw lignin (AIL + ASL)91.35 — — Self-precipitated lignin — — 9.60 (MMW) Precipitated lignin* —— 32.12 (LMW) Very low molecular wt. — — 11.72 lignin (VLMW) Residuallignin (HMW) — 11.33 — Total: 91.35 11.33 53102.68 *recovered from theliquor by precipitation with water; AIL—acid-insoluble lignin;ASL—acid-soluble lignin

The potential of the washed pulp for production of ethanol was evaluatedin 100-mL Erlenmeyer flasks. The pH of the washed pulp was firstadjusted with a water ammonia solution to pH 5.50, then placed intoErlenmeyer flasks and resuspended in distilled water to a total reactionweight of 100 g (including the yeast and enzyme weight, the finalreaction volume was ˜100 mL) and a final solids concentration of 16%(w/w). The ethanol production process was run according to asimultaneous saccharification and fermentation scheme (SSF) using acommercial Trichoderma reesei fungal cellulase preparation Celluclast®1.5 L (Celluclast is a registered trademark of Novozymes AIS Corp.,Bagsvaerd, Denmark) at 15 FPU g⁻¹ glucan supplemented with a commercialbeta-glucosidase preparation (30 CBU glucan) and a ethanologenic yeast,Saccharomyces cerevisiae strain Y-1528 (available from the AgriculturalResearch Service, United States Department of Agriculture, Peoria, Ill.,USA) at 10 g/L dry cell wt. capable of fermenting all hexoses. Themixture was incubated at 36° C., 150 rpm for 48 h. Samples were takenfor ethanol analysis by gas chromatography at 0, 24, 36, and 48 h. Theethanol yield obtained was 39.40% theoretical ethanol yield based oninitial hexose input. The final ethanol beer concentration was 3.26%(w/w) (FIGS. 7 a and 7 b).

Example 2

Duplicate 200-g samples of the wood chips prepared in Example 1,designated as ASP2, were used for this study. The aspen chips wereorganosolv-pretreated in aqueous ethanol (50% w/w ethanol) with noaddition of exogenous acid or base, in a 2-L Parr® reactor. Duplicate200 g (ODW) samples of aspen chips were cooked at 195° C. for 90 nun.The liquor:wood ratio was 5:1 (w:w). After cooking, the reactor wascooled to room temperature. Solids and liquids were then separated byfiltration. Solids were intensively washed with a hot ethanol solution(70° C.) followed by a tap water wash step. The moisture content of thewashed pulp was reduced to about 40% with the help of a hydraulic press(alternatively a screw press can be used). The washed pulp washomogenized and stored in a fridge at 4° C. The chemical composition(hexose, pentose, lignin content) of raw chips, washed, and unwashedpulps was determined according to a modified Klason lignin methodderived from the Technical Association of Pulp and Paper Industry(TAPPI) standard method T222 om-88 (TAPPI methods in CD-ROM, 2004, TAPPIPress). Liquids were analyzed for carbohydrate degradation products(furfural, 5-hydromethylfurfural), acids, and oligo- and monosaccharidesaccording to standard procedures established by the National RenewableEnergy Laboratory (NREL, Golden, Colo., USA). The resulting data wereused to calculate overall carbohydrate and lignin recoveries and processmass balance. The carbohydrate composition and overall carbohydraterecoveries from the raw and pretreated aspen chips are shown in Table 3.230.2 g (odw) of pulp were recovered after batch organosolv processingof 400 g of aspen wood chips (57.6% pulp yield), and comprised mainlyfermentable-into-ethanol carbohydrates. Pentoses and hexoses werepartially degraded resulting in 0.53 g Kg⁻¹ of furfural and 0.05 g Kg⁻¹of 5-HMF, respectively. The lignin content in the raw aspen chips andoverall lignin recovery after pretreatment are shown in Table 4.

TABLE 3 Carbohydrate content of raw and pretreated aspen chips (ASP2pretreatment conditions) and overall carbohydrate recovery RawPretreated Feedstock Raw Feedstock Output Carbohydrates Recovery chipsInput Pulp Liquor Total Soluble Insoluble Total Component (%) (g) (g)(g) (g) (%) (%) (%) Arabinan 0.44 1.75 0 0.22 0.22 12.54 0.00 12.54Galactan 0.43 1.71 0 0.21 0.21 12.25 0.00 12.25 Glucan 48.76 195.03194.50 0.37 194.87 0.19 99.73 99.92 Xylan 16.44 65.75 14.80 6.76 21.5610.28 22.51 32.79 Mannan 1.48 5.92 4.07 0.34 4.41 5.74 68.78 74.52Total: 67.55 270.16 213.37 7.9 221.27

TABLE 4 Lignin input in raw aspen chips and lignin fractions recoveredafter organosolv pretreatment (ASP2 pretreatment conditions) RawPretreated Pretreated Feedstock Feedstock Feedstock Input Solids OutputLiquids Output Component (g) (odw, g) (odw, g) Raw lignin (AIL + ASL)91.35 — — Self-precipitated lignin — —  9.14 (MMW) Precipitated lignin*— — 43.09 (LMW) Very low molecular wt. — — 12.60 lignin (VLMW) Residuallignin (HMW) — 7.32 — Total: 91.35 7.32 64.83 *recovered from the liquorby precipitation with water; AIL—acid-insoluble lignin; ASL—acid-solublelignin

Production of ethanol from the washed pulp was evaluated in 100-mLErlenmeyer flasks. The experiments in Erlenmeyer flasks were run asfollows. The pH of the washed pulp was adjusted with a water ammoniasolution to pH 5.50, then placed into Erlenmeyer flasks and resuspendedin distilled water to a total reaction weight of 100 g (including theyeast and enzyme weight, the total reaction volume was ˜100 mL) and afinal solids concentration of 16% (w/w). The ethanol process was runaccording to a SSF using a commercial Trichoderma reesei fungalcellulase preparation Celluclast® 1.5 L at 15 FPU g⁻¹ glucansupplemented with a commercial beta-glucosidase preparation (30 CBU g⁻¹glucan) and an ethanologenic yeast, Saccharomyces cerevisiae strainY-1528 at 10 g/L dry cell wt. capable of fermenting all hexoses. Themixture was incubated at 36° C., 150 rpm for 48 h. Samples were takenfor ethanol analysis by gas chromatography at 0, 24, 36, and 48 h. Theethanol yield obtained was 79.30% theoretical ethanol yield based oninitial hexose input. The final ethanol beer concentration was 6.33%(w/w) (FIGS. 7 a and 7 b).

Example 3

Duplicate 200-g samples of the wood chips prepared in Example 1,designated as ASP3, were used for this study. The aspen chips wereorganosolv-pretreated in aqueous ethanol (50% w/w ethanol) with noaddition of exogenous acid or base, in a 2-L Parr® reactor. Theduplicate samples of aspen chips were cooked in duplicate at 195° C. for120 min. The liquor:wood ratio was 5:1 (w:w). After cooking, the reactorwas cooled to room temperature. Solids and liquids were then separatedby filtration. Solids were intensively washed with a hot ethanolsolution (70° C.) followed by a tap water wash step. The moisturecontent of the washed pulp was reduced to about 40% with the help of ahydraulic press (alternatively a screw press can be used). The washedpulp was homogenized and stored in a fridge at 4° C. The chemicalcomposition (hexose, pentose, lignin content) of raw chips, washed, andunwashed pulps was determined according to a modified Klason ligninmethod derived from the Technical Association of Pulp and Paper Industry(TAPPI) standard method T222 om-88. Liquids were analyzed forcarbohydrate degradation products (furfural, 5-hydromethylfurfural),acids, and oligo- and monosaccharides according to standard proceduresestablished by the National Renewable Energy Laboratory. The resultingdata were used to calculate overall carbohydrate and lignin recoveriesand process mass balance. The carbohydrate composition and overallcarbohydrate recoveries from the raw and pretreated aspen chips areshown in Table 5. 219.9 g (odw) of pulp were recovered after batchorganosolv processing of 400 g of aspen wood chips (54.98% pulp yield)containing mainly fermentable-into-ethanol carbohydrates. Pentoses andhexoses were partially degraded resulting in 0.92 g Kg⁻¹ of furfural and0.08 g Kg⁻¹ of 5-HMF, respectively. The lignin contents in raw aspenchips and overall lignin recovery after pretreatment are shown in Table6.

Production of ethanol from the washed pulp was evaluated in 100-mLErlenmeyer flasks. The experiments in Erlenmeyer flasks were run asfollows. The pH of the washed pulp was adjusted with a water ammoniasolution to pH 5.50, placed into Erlenmeyer flasks and resuspended indistilled water to a total reaction weight of 100 g (including the yeastand enzyme weight, the total reaction volume was ˜100 mL) and a finalsolids concentration of 16% (w/w). The ethanol process was run accordingto a SSF scheme using a commercial Trichoderma reesei fungal cellulasepreparation Celluclast® 1.5 L at 15 FPU g⁻¹ glucan supplemented with acommercial beta-glucosidase preparation (30 CBU g⁻¹ glucan) and anethanologenic yeast, Saccharomyces cerevisiae strain Y-1528 at 10 g/Ldry cell wt. capable of fermenting all hexoses. The mixture wasincubated at 36° C., 150 rpm for 48 h. Samples were taken for ethanolanalysis by gas chromatography at 0, 24, 36, and 48 h. The ethanol yieldobtained was 79.00% theoretical ethanol yield based on initial hexoseinput. The final ethanol beer concentration was 6.60% (w/w) (FIGS. 7 aand 7 b).

TABLE 5 Carbohydrate content of raw and pretreated aspen chips (ASP3pretreatment conditions) and overall carbohydrate recovery RawPretreated Feedstock Raw Feedstock Output Carbohydrates Recovery chipsInput Pulp Liquor Total Soluble Insoluble Total Component (%) (g) (g)(g) (g) (%) (%) (%) Arabinan 0.44 1.75 0 0.10 0.10 5.70 0 5.70 Galactan0.43 1.71 0 0.15 0.15 8.75 0 8.75 Glucan 48.76 195.03 186.63 0.33 186.960.17 95.69 95.86 Xylan 16.44 65.75 12.56 4.03 16.59 6.13 19.10 25.23Mannan 1.48 5.92 3.50 0.30 3.80 5.06 59.02 64.08 Total: 67.55 270.16202.69 4.91 207.6

TABLE 6 Lignin input in raw aspen chips and lignin fractions recoveredafter organosolv pretreatment (ASP3 pretreatment conditions) RawPretreated Pretreated Feedstock Feedstock Feedstock Input Solids OutputLiquids Output Component (g) (odw, g) (odw, g) Raw lignin (AIL + ASL)91.35 — — Self-precipitated lignin — — 0.16 (MMW) Precipitated lignin* —— 40.70 (LMW) Very low molecular wt. — — 11.46 lignin (VLMW) Residuallignin (HMW) — 6.47 — Total: 91.35 6.47 5297.8232 *recovered from theliquor by precipitation with water; AIL—acid-insoluble lignin;ASL—acid-soluble lignin

Example 4

Representative samples of British Columbian beetle-killed lodgepole pine(Pinus contorta) sapwood (˜120 years old) were collected. Afterharvesting, logs were debarked, split, chipped, and milled to a chipsize of approximately ≦10 mm×10 mm×3 mm. Chips were stored at roomtemperature (moisture content at equilibrium was ˜10%). Duplicate 200-gsamples of these wood chips, designated as BKLLP1, were used for thisstudy. The chips were organosolv-pretreated in aqueous ethanol (50% w/wethanol) with addition of 1.10% (w/w) sulfuric acid, in a 2-L Parr®reactor. The chips were cooked in duplicate at 170° C. for 60 min. Theliquor:wood ratio was 5:1 (w:w). After cooking, the reactor was cooledto room temperature. Solids and liquids were then separated byfiltration. Solids were intensively washed with a hot ethanol solution(70° C.) followed by a tap water wash step. The moisture content of thewashed pulp was reduced to about 40% with the help of a hydraulic press(alternatively a screw press can be used). The washed pulp washomogenized and stored in a fridge at 4° C. The chemical composition(hexose, pentose, lignin content) of raw chips, washed, and unwashedpulps was determined according to a modified Klason lignin methodderived from the Technical Association of Pulp and Paper Industry(TAPPI) standard method T222 om-88. Liquids were analyzed forcarbohydrate degradation products (furfural, 5-hydromethylfurfural),acids, and oligo- and monosaccharides according to standard proceduresestablished by the National Renewable Energy Laboratory. The obtaineddata were used to calculate overall carbohydrate and lignin recoveriesand process mass balance. The carbohydrate composition and the overallcarbohydrate recoveries from the raw and pretreated beetle-killedlodgepole pine chips are shown in Table 7. 177.2 g (odw) of pulp wererecovered after batch organosolv processing of 400 g of wood chips(44.30% pulp yield) containing mainly fermentable-into-ethanolcarbohydrates. Pentoses and hexoses were partially degraded resulting in0.72 g Kg⁻¹ of furfural and 1.78 g Kg⁻¹ of 5-HMF, respectively. Thelignin content in raw beetle-killed lodgepole pine chips and overalllignin recovery after pretreatment are shown in Table 8.

TABLE 7 Carbohydrate content of raw and pretreated beetle-killedlodgepole pine chips (BKLLP1 pretreatment conditions) and overallcarbohydrate recovery Raw Pretreated Feedstock Raw Feedstock OutputCarbohydrates Recovery chips Input Pulp Liquor Total Soluble InsolubleTotal Component (%) (g) (g) (g) (g) (%) (%) (%) Arabinan 1.76 7.03 0.050.77 0.82 10.96 0.76 11.72 Galactan 2.01 8.05 0.35 1.25 1.60 15.52 4.4019.92 Glucan 45.55 182.22 150.44 4.37 154.81 2.40 82.56 84.96 Xylan 7.2228.90 3.58 1.64 5.22 5.68 12.39 18.07 Mannan 11.07 44.29 6.06 0.00 6.060.00 13.68 13.68 Total: 67.61 270.49 160.48 8.03 168.51

TABLE 8 Lignin input in raw beetle-killed lodgepole pine chips andlignin fractions recovered after organosolv pretreatment (BKLLP1pretreatment conditions) Raw Pretreated Pretreated Feedstock FeedstockFeedstock Input Solids Output Liquids Output Component (g) (odw, g)(odw, g) Raw lignin (AIL + ASL) 106.85 — — Self-precipitated lignin — — 0.17 (MMW) Precipitated lignin* — — 28.10 (LMW) Very low molecular wt.— — 13.47 lignin (VLMW) Residual lignin (HMW) — 15.29 — Total: 106.8515.29 41.74 *recovered from the liquor by precipitation with water;AIL—acid-insoluble lignin; ASL—acid-soluble lignin

Production of ethanol from the washed pulp was evaluated in 100-mLErlenmeyer flasks. The experiments in Erlenmeyer flasks were run asfollows. The pH of the washed pulp was adjusted with a water ammoniasolution to pH 5.50, placed into Erlenmeyer flasks and resuspended indistilled water to a total reaction weight of 100 g (including the yeastand enzyme weight, the total reaction volume was ˜100 mL) and a finalsolids concentration of 16% (w/w). The ethanol process was run accordingto a simultaneous saccharification and fermentation scheme (SSF) using acommercial Trichoderma reesei fungal cellulase preparation Celluclast®1.5 L at 15 FPU g⁻¹ glucan supplemented with a commercialbeta-glucosidase preparation (30 CBU g⁻¹ glucan) together with anethanologenic yeast, Saccharomyces cerevisiae strain Y-1528 at 10 g/Ldry cell wt. capable of fermenting all hexoses. The mixture wasincubated at 36° C., 150 rpm for 48 h. Samples were taken for ethanolanalysis by gas chromatography at 0, 24, 36, and 48 h. The ethanol yieldobtained was 60.50% theoretical ethanol yield based on initial hexoseinput. The final ethanol beer concentration was 7.18% (w/w) (FIGS. 8 aand 8 b).

Example 5

Duplicate 200-g samples British Columbian beetle-killed lodgepole pine(Pinus contorta), designated as BKLLP2, of the chips prepared for thestudy described in the Example 4, were organosolv-pretreated in aqueousethanol (50% w/w ethanol) with addition of 1.10% (w/w) sulphuric acid,in a 2-L Parr® reactor. Duplicate 200-g (ODW) samples of chips werecooked at 175° C. for 60 min. The liquor:wood ratio was 5:1 (w:w). Aftercooking, the reactor was cooled to room temperature. Solids and liquidswere then separated by filtration. Solids were intensively washed with ahot ethanol solution (70° C.) followed by a tap water wash step. Themoisture content of the washed pulp was reduced to about 40% with thehelp of a hydraulic press (alternatively a screw press can be used). Thewashed pulp was homogenized and stored in a fridge at 4° C. The chemicalcomposition (hexose, pentose, lignin content) of raw chips, washed, andunwashed pulps was determined according to a modified Klason ligninmethod derived from the Technical Association of Pulp and Paper Industry(TAPPI) standard method T222 om-88. Liquids were analyzed forcarbohydrate degradation products (furfural, 5-hydromethylfurfural),acids, and oligo- and monosaccharides according to standard proceduresestablished by the National Renewable Energy Laboratory. The resultingdata were used to calculate overall carbohydrate and lignin recoveriesand process mass balance. The carbohydrate composition and the overallcarbohydrate recoveries from the raw and pretreated beetle-killedlodgepole pine chips are shown in Table 9. 144.4 g (odw) of pulp wererecovered after batch organosolv processing of 400 g of wood chips(36.10% pulp yield) containing mainly fermentable-into-ethanolcarbohydrates. Pentoses and hexoses were partially degraded resulting in0.92 g Kg⁻¹ of furfural and 1.87 g Kg⁻¹ of 5-HMF, respectively. Thelignin content in raw beetle-killed lodgepole pine chips and overalllignin recovery after pretreatment are shown in Table 10.

TABLE 9 Carbohydrate content of raw and pretreated beetle-killedlodgepole pine chips (BKLLP2 pretreatment conditions) and overallcarbohydrate recovery Raw Pretreated Feedstock Raw Feedstock OutputCarbohydrates Recovery chips Input Pulp Liquor Total Soluble InsolubleTotal Component (%) (g) (g) (g) (g) (%) (%) (%) Arabinan 1.76 7.03 0.040.39 0.43 5.55 0.62 6.17 Galactan 2.01 8.05 0.03 0.79 0.82 9.81 0.3610.17 Glucan 45.55 182.22 134.08 5.28 139.36 2.90 73.58 76.48 Xylan 7.2228.90 1.59 0.65 2.24 2.25 5.50 7.75 Mannan 11.07 44.29 2.30 0 2.30 05.18 5.18 Total: 67.61 270.49 138.04 7.11 145.15

TABLE 10 Lignin input in raw beetle-killed lodgepole pine chips andlignin fractions recovered after organosolv pretreatment (BKLLP2pretreatment conditions) Raw Pretreated Pretreated Feedstock FeedstockFeedstock Input Solids Output Liquids Output Component (g) (odw, g)(odw, g) Raw lignin (AIL + ASL) 106.85 — — Self-precipitated lignin — — 0.13 (MMW) Precipitated lignin* — — 33.01 (LMW) Very low molecular wt.— — 11.88 lignin (VLMW) Residual lignin (HMW) — 7.15 — Total: 106.857.15 45.02 *recovered from the liquor by precipitation with water;AIL—acid-insoluble lignin; ASL—acid-soluble lignin

Production of ethanol from the washed pulp was evaluated in 100-mLErlenmeyer flasks. The experiments were run as follows. The pH of thewashed pulp was adjusted with a water ammonia solution to pH 5.50,placed into Erlenmeyer flasks and resuspended in distilled water to atotal reaction weight of 100 g (including the yeast and enzyme weight,the total reaction volume was ˜100 mL) and a final solids concentrationof 16% (w/w). The ethanol process was run according to a simultaneoussaccharification and fermentation scheme (SSF) using a commercialTrichoderma reesei fungal cellulase preparation Celluelast® 1.5 L at 15FPU g⁻¹ glucan supplemented with a commercial beta-glucosidasepreparation (30 CBU g⁻¹ glucan) and an ethanologenic yeast,Saccharomyces cerevisiae strain Y-1528 at 10 g/L dry cell wt. capable offermenting all hexoses. The mixture was incubated at 36° C., 150 rpm for48 h. Samples were taken for ethanol analysis by gas chromatography at0, 24, 36, and 48 h. The ethanol yield obtained was 53.10% theoreticalethanol yield based on initial hexose input. The final ethanol beerconcentration was 7.74% (w/w) (FIGS. 8 a and 8 b).

Example 6

Duplicate 200-g samples British Columbian beetle-killed lodgepole pine(Pinus contorta), designated as BKLLP3, chips prepared for the studydescribed in the Example 4, were organosolv-pretreated in aqueousethanol (50% w/w ethanol) with addition of 1.10% (w/w) sulphuric acid,in a 2-L Parr® reactor chips were cooked in duplicate at 180° C. for 60min. The liquor:wood ratio was 5:1 (w:w). After cooking, the reactor wascooled to room temperature. Solids and liquids were then separated byfiltration. Solids were intensively washed with a hot ethanol solution(70° C.) followed by a tap water wash step. The moisture content of thewashed pulp was reduced to about 40% with the help of a hydraulic press(alternatively a screw press can be used). The washed pulp washomogenized and stored in a fridge at 4° C. The chemical composition(hexose, pentose, lignin content) of raw chips, washed, and unwashedpulps was determined according to a modified Klason lignin methodderived from the Technical Association of Pulp and Paper Industry(TAPPI) standard method T222 om-88. Liquids were analyzed forcarbohydrate degradation products (furfural, 5-hydromethylfurfural),acids, and oligo- and monosaccharides according to standard proceduresestablished by the National Renewable Energy Laboratory. The resultingdata were used to calculate overall carbohydrate and lignin recoveriesand process mass balance. The carbohydrate composition and the overallcarbohydrate recoveries from the raw and pretreated beetle-killedlodgepole pine chips are shown in Table 11. 120.7 g (odw) of pulp wasrecovered after batch organosols processing of 400 g of wood chips(30.18% pulp yield) containing mainly fermentable into ethanolcarbohydrates. Pentoses and hexoses were partially degraded resulting in1.47 g Kg⁻¹ of furfural and 2.17 g Kg⁻¹ of 5-HMF, respectively. Thelignin content in raw aspen chips and overall lignin recovery afterpretreatment are shown in Table 12.

TABLE 11 Carbohydrate content of raw and pretreated beetle-killedlodgepole pine chips (BKLLP3 pretreatment conditions) and overallcarbohydrate recovery Raw Pretreated Feedstock Raw Feedstock OutputCarbohydrates Recovery chips Input Pulp Liquor Total Soluble InsolubleTotal Component (%) (g) (g) (g) (g) (%) (%) (%) Arabinan 1.76 7.03 0.040.22 0.26 3.13 0.52 3.65 Galactan 2.01 8.05 0.33 0.61 0.94 7.57 4.0511.62 Glucan 45.55 182.22 102.34 6.15 108.49 3.38 56.16 59.54 Xylan 7.2228.90 2.34 0.41 2.75 1.42 8.10 9.52 Mannan 11.07 44.29 3.86 2.07 5.934.67 8.72 13.39 Total: 67.61 270.49 108.91 9.46 118.37

TABLE 12 Lignin input in raw beetle-killed lodgepole pine chips andlignin fractions recovered after organosolv pretreatment (BKLLP3pretreatment conditions) Raw Pretreated Pretreated Feedstock FeedstockFeedstock Input Solids Output Liquids Output Component (g) (odw, g)(odw, g) Raw lignin (AIL + ASL) 106.85 — — Self-precipitated lignin — — 0.26 (MMW) Precipitated lignin* — — 33.64 (LMW) Very low molecular wt.— — 15.33 lignin (VLMW) Residual lignin (HMW) — 9.11 — Total: 106.859.11 49.23 *recovered from the liquor by precipitation with water;AIL—acid-insoluble lignin; ASL—acid-soluble lignin

Production of ethanol from the washed pulp was evaluated in 100-mLErlenmeyer flasks. The experiments in Erlenmeyer flasks were run asfollows. The pH of the washed pulp was adjusted with a water ammoniasolution to pH 5.50, placed into Erlenmeyer flasks and resuspended indistilled water to a total reaction weight of 100 g (including the yeastand enzyme weight, the total reaction volume was ˜100 mL) and a finalsolids concentration of 16% (w/w). The ethanol process was run accordingto a SSF scheme using a commercial Trichoderma reesei fungal cellulasepreparation Celluclast® 1.5 L at 15 FPU g⁻¹ glucan supplemented with acommercial beta-glucosidase preparation (30 CBU g⁻¹ glucan) and anethanologenic yeast, Saccharomyces cerevisiae strain Y-1528 at 10 g/Ldry cell wt. capable of fermenting all hexoses. The mixture wasincubated at 36° C., 150 rpm for 48 h. Samples were taken for ethanolanalysis by gas chromatography at 0, 24, 36, and 48 h. The ethanol yieldobtained was 44.60% theoretical ethanol yield based on initial hexoseinput. The final ethanol beer concentration was 7.79% (w/w) (FIGS. 8 aand 8 b).

Example 7

Representative samples of wheat straw (Triticum sp.) from EasternWashington, USA were collected. Wheat straw was cut into ˜5-cm chips andstored at room temperature (moisture content at equilibrium was ˜10%).The straw was organosols-pretreated in aqueous ethanol (50% w/w ethanol)with no addition of exogenous acid or base, in a 2-L Parr® reactor.Duplicate100-g (ODW) samples of wheat straw, designated as WS-1, werecooked in duplicate at 195° C. for 90 min. The liquor:raw material ratiowas 10:1 (w/w). After cooking, the reactor was cooled to roomtemperature. Solids and the spent liquor were then separated byfiltration. Solids were intensively washed with a hot ethanol solution(70° C.) followed by a tap water wash step. The moisture content of thewashed pulp was reduced to about 50% with the help of a hydraulic press(alternatively a screw press can be used). The washed pulp washomogenized and stored in a fridge at 4° C. The chemical compositions(hexose, pentose, lignin content) of washed and unwashed pulps weredetermined according to a modified Mason lignin method derived from theTechnical Association of Pulp and Paper Industry (TAPPI) standard methodT222 em-88. Liquids were analyzed for carbohydrate degradation products(furfural, 5-hydromethylfurfural), acids, and oligo- and monosaccharidesaccording to standard procedures established by the National RenewableEnergy Laboratory. The resulting data were used to calculate overallcarbohydrate and lignin recoveries and process mass balance. Thecarbohydrate composition and the overall carbohydrate recoveries fromthe raw and pretreated wheat straw are shown in Table 13. 46.8 g(oven-dried weight, odw) of WS-1 pulp was recovered after batchorganosolv processing of 100 g of wheat straw (46.8% pulp yield)containing mainly fermentable-into-ethanol carbohydrates. Pentoses andhexoses were partially degraded resulting in 0.39 g Kg⁻¹ of furfural and0.03 g Kg⁻¹ of 5-HMF, respectively. The lignin content in raw wheatstraw and overall lignin recovery after pretreatment are shown in Table14.

TABLE 13 Carbohydrate content of raw and pretreated wheat straw chips(WS-1 pretreatment conditions) and overall carbohydrate recovery RawPretreated Feedstock Raw Feedstock Output Carbohydrates Recovery chipsInput Pulp Liquor Total Soluble Insoluble Total Component (%) (g) (g)(g) (g) (%) (%) (%) Arabinan 3.85 3.85 0.00 0.17 0.17 4.39 0.00 4.39Galactan 1.16 1.16 0.00 0.19 0.19 16.72 0.00 16.72 Glucan 54.92 54.9235.47 0.00 35.47 0.00 64.58 64.58 Xylan 27.83 27.83 3.36 2.68 6.03 9.6212.06 21.67 Mannan 0.53 0.53 0.00 0.08 0.08 15.78 0.00 15.78 Total:88.30 88.30 38.83 3.12 41.94

TABLE 14 Lignin input in raw wheat straw chips and lignin fractionsrecovered after organosolv pretreatment (WS-1 pretreatment conditions)Raw Pretreated Pretreated Feedstock Feedstock Feedstock Input SolidsOutput Liquids Output Component (g) (odw, g) (odw, g) Raw lignin (AIL +ASL) 17.44 — — Self-precipitated lignin — — 1.7 (MMW) Precipitatedlignin* — — 8.4 (LMW) Very low molecular wt. — — — lignin (VLMW)Residual lignin (HMW) — 4.31 — Total: 17.44 4.31 10.1  *recovered fromthe liquor by precipitation with water; AIL—acid-insoluble lignin;ASL—acid-soluble lignin

The potential of the produced washed wheat straw pulp for production ofethanol was evaluated in 100-mL Erlenmeyer flasks. The experiments inErlenmeyer flasks were run as follows. The pH of the washed pulp wasadjusted with a water ammonia solution to pH 5.50, placed intoErlenmeyer flasks and resuspended in distilled water to a total reactionweight of 100 g (including the yeast and enzyme weight, the finalreaction volume was ˜100 mL) and a final solids concentration of 16%(w/w). The ethanol process was run according to a SSF scheme using acommercial Trichoderma reesei fungal cellulase preparation Celluclast®1.5 L at 15 FPU g⁻¹ glucan supplemented with a commercialbeta-glucosidase preparation (30 CBU g⁻¹ glucan) and an ethanologenicyeast, Saccharomyces cerevisiae strain Y-1528 at 10 g/L dry cell wt.capable of fermenting all hexoses. The mixture was incubated at 36° C.,150 rpm for 48 h. Samples were taken for ethanol analysis by gaschromatography at 0, 24, 36, and 48 h. The ethanol yield obtained was88.86% theoretical ethanol yield based on initial hexose input. Thefinal ethanol beer concentration was 6.14% (w/w) (FIGS. 9 a and 9 b).

Example 8

Representative samples of switchgrass (Panicum virgatum) from Tennessee,USA were collected. The switchgrass samples were cut to a particle sizeof approximately 5 cm and stored at room temperature (moisture contentat equilibrium was ˜10%). The switchgrass chips wereorganosolv-pretreated in aqueous ethanol (50% w/w ethanol) with noaddition of exogenous acid or base, in a 2-L Parr® reactor.Dubplicate100-g (odw) switchgrass samples designated as SWG-1, werecooked at 195° C. for 90 min. The liquor:raw material ratio was 10:1(w/w). After cooking, the reactor was cooled to room temperature. Solidsand the spent liquor were then separated by filtration. Solids wereintensively washed with a hot ethanol solution (70° C.) followed by atap water wash step. The moisture content of the washed pulp was reducedto about 50% with the help of a hydraulic press (alternatively a screwpress can be used). The washed pulp was homogenized and stored in afridge at 4° C. The chemical composition (hexose, pentose, lignincontent) of washed and unwashed pulps was determined according to amodified Klason lignin method derived from the Technical Association ofPulp and Paper Industry (TAPPI) standard method T222 om-88. Liquids wereanalyzed for carbohydrate degradation products (furfural,5-hydromethylfurfural), acids, and oligo- and monosaccharides accordingto standard procedures established by the National Renewable EnergyLaboratory. The resulting data were used to calculate overallcarbohydrate and lignin recoveries and process mass balance. Thecarbohydrate composition and the overall carbohydrate recoveries fromthe raw and pretreated switchgrass are illustrated in Table 15. 45.2 g(oven-dried weight, odw) of SWG-1 pulp was recovered after batchorganosolv processing of 100 g of switchgrass (45.2% pulp yield)containing mainly fermentable-into-ethanol carbohydrates. Pentoses andhexoses were partially degraded resulting in 0.917 g Kg⁻¹ of furfuraland 0.21 g Kg⁻¹ of 5-HMF, respectively. The lignin content in rawswitchgrass and overall lignin recovery after pretreatment are shown inTable 16.

TABLE 15 Carbohydrate content of raw and pretreated switchgrassparticles (SWG-1 pretreatment conditions) and overall carbohydraterecovery Raw Pretreated Feedstock Raw Feedstock Output CarbohydratesRecovery chips Input Pulp Liquor Total Soluble Insoluble Total Component(%) (g) (g) (g) (g) (%) (%) (%) Arabinan 3.44 3.44 0.00 0.23 0.23 6.790.00 6.79 Galactan 0.93 0.93 0.00 0.18 0.18 19.48 0.00 19.48 Glucan51.04 51.04 35.88 1.37 37.25 2.68 70.31 72.99 Xylan 26.69 26.69 5.373.01 8.39 11.29 20.14 31.43 Mannan 0.00 0.00 0.00 0.00 0.00 0.00 0.000.00 Total: 82.10 82.10 41.26 4.80 46.05

TABLE 16 Lignin input in raw switchgrass particles and lignin fractionsrecovered after organosolv pretreatment (SWG-1 pretreatment conditions)Raw Pretreated Pretreated Feedstock Feedstock Feedstock Input SolidsOutput Liquids Output Component (g) (odw, g) (odw, g) Raw lignin (AIL +ASL) 18.17 — — Self-precipitated lignin — —  3.00 (MMW) Precipitatedlignin* — — 10.6  (LMW) Very low molecular wt. — — — lignin (VLMW)Residual lignin (HMW) — 2.67 — Total: 18.17 2.67 13.60 *recovered fromthe liquor by precipitation with water; AIL—acid-insoluble lignin;ASL—acid-soluble lignin

The potential of the produced washed switchgrass pulp for production ofethanol was evaluated in 100-mL Erlenmeyer flasks. The experiments inErlenmeyer flasks were run as follows. The pH of the washed pulp wasadjusted with a water ammonia solution to pH 5.50, placed intoErlenmeyer flasks and resuspended in distilled water to a total reactionweight of 100 g (including the yeast and enzyme weight, the finalreaction volume was ˜100 mL) and a final solids concentration of 16%(w/w). The ethanol process was run according to a SSE scheme using acommercial Trichoderma reesei fungal cellulase preparation Celluclast®1.5 L at 15 FPU g⁻¹ glucan supplemented with a commercialbeta-glucosidase preparation (30 CBU g⁻¹ glucan) and an ethanologenicyeast, Saccharomyces cerevisiae strain Y-1528 at 10 g/L dry cell wt.capable of fermenting all hexoses. The mixture was incubated at 36° C.,150 rpm for 48 h. Samples were taken for ethanol analysis by gaschromatography at 0, 24, 36, and 48 h. The ethanol yield obtained was82.51% theoretical ethanol yield based on initial hexose input. Thefinal ethanol beer concentration was 5.97% (w/w) (FIGS. 9 a and 9 b).

While this invention has been described with respect to the exemplaryembodiments, those skilled in these arts will understand how to modifyand adapt the systems, processes and equipment configurations disclosedherein for continuously receiving and controllably comminglinglignocellulosic feedstocks with counter-flowing organic solvents.Certain novel elements disclosed herein for processing a continuousincoming stream of lignocellulosic feedstocks with countercurrentflowing or alternatively, concurrent flowing organic solvents forseparating the lignocellulosic materials into component parts andfurther processing thereof, can be modified for integration into batchsystems configured for processing lignocellulosic materials. Forexample, the black liquors produced in batch systems may be de-lignifiedand then a portion of the de-lignified black liquor used to pretreat anew, fresh batch of lignocellulosic materials prior to batch organosolvcooking, while the remainder of the de-lignified black liquor is furtherprocessed into component parts as disclosed herein. Specifically, thefresh batch of lignocellulosic materials maybe controllably commingledwith portions of the de-lignified black liquor for selected periods oftime prior to contacting, commingling and impregnating the batch oflignocellulosic materials with suitable organic solvents. Also, it iswithin the scope of the present invention, to provide turbulence withina batch digestion system wherein a batch of lignocellulosic materials iscooked with organic solvents by providing pressurized flows of theorganic solvents within and about the digestion vessel. It is optionalto controllably remove portions of the organic solvent/black liquorsfrom the digestion vessel during the cooking period and concurrentlyintroduced fresh organic solvent and/or de-lignified black liquorsthereby facilitating and expediting delignification of thelignocellulosic materials. It is also within the scope of the presentinvention to further process the de-lignified black liquors from thebatch lignocellulosic digestion systems to separate and further processcomponents parts exemplified by lignins, furfural, acetic acid,monosaccharides, oligosaccharides, and ethanol among others.

1. A modular system for organosolv fractionation of lignocellulosicfeedstock into component parts and further processing of said componentparts; the modular process comprising: a first processing moduleconfigured for receiving, physically processing, and physico-chemicallydigesting a lignocellulose feedstock with a separately supplied organicsolvent thereby extracting component parts therefrom said feedstock, andseparating said component parts into a cellulosic solids fraction and afirst liquid fraction; a second processing module configured forreceiving therein said cellulosic solids fraction and for separatingtherefrom at least ethanol, a first class of lignin derivatives, and ade-lignified stillage; a third processing module configured forseparating the first liquid fraction into a second class of ligninderivatives, a third class of lignin derivatives and a filtrate, foroptionally separating furfurals from said filtrate, and for recovering aportion of the organic solvent from the filtrate by distillation therebyproducing a first stillage; and a fourth processing module configuredfor separating the first stillage into one or more of an aceticacid-containing liquid fraction, a fourth class of lignin derivatives, asugar syrup, and a semi-solid waste material.
 2. A modular systemaccording to claim 1, additionally provided with a fifth processingmodule configured for anaerobic digestion and processing of thesemi-solid waste material separated by the fourth processing module,into at least a collectable biogas and an liquid effluent.
 3. A modularsystem according to claim 1, wherein the first processing modulecomprises a plurality of equipment selected and configured forcontrollable and manipulable communication and cooperation for:receiving therein a lignocellulosic feedstock; processing thelignocellulosic feedstock by physically separating non-lignocellulosicmaterials therefrom; physico-chemically digesting the processedlignocellulosic feedstock by commingling said feedstock with aseparately supplied organic solvent while controllably manipulating atleast the temperature and pressure therein and thereabout, therebyproducing the cellulosic solids fraction and the first liquid fraction;and separately and controllably discharging the cellulosic solidsfraction and the first liquid fraction.
 4. A modular system according toclaim 1, wherein the first processing module is configured tocontinuously receive, physically process, and physico-chemically digesta lignocellulosic feedstock thereby continuously producing thecellulosic solids fraction and the first liquid fraction.
 5. A modularsystem according to claim 1, wherein the first processing module isconfigured to receive, physically process, and physico-chemically digesta batch of lignocellulosic feedstock thereby producing the cellulosicsolids fraction and the first liquid fraction.
 6. A modular systemaccording to claim 1, wherein the first processing module is providedwith a temperature-controllable and pressure-controllable digestionvessel configured to: receive therein the processed lignocellulosic feedstock at about a first end and to convey said feedstock therethrough toabout a second end; receive therein an organic solvent at about thesecond end, and to flow said organic solvent therethrough to about thefirst end; discharge the cellulosic solids fraction through an outletprovided therefor approximate the second end; and discharge the firstliquid fraction through an outlet provided therefor approximate thefirst end.
 7. A modular system according to claim 6, wherein thetemperature-controllable and pressure-controllable digestion vessel isconfigured to: receive therein the processed lignocellulosic feed stockat about a first end and to convey said feedstock therethrough to abouta second end; receive therein an organic solvent at about the first end,and to circulate said organic solvent therethrough and thereabout;discharge the cellulosic solids fraction through an outlet providedtherefor approximate the second end; and discharge the first liquidfraction through an outlet provided therefor approximate the second end.8. A modular system according to claim 6, wherein thetemperature-controllable and pressure-controllable digestion vessel isconfigured to: receive therein the processed lignocellulosic feed stockat about a first end and to convey said feedstock therethrough to abouta second end; receive therein an organic solvent interposed the firstend and second end, and to circulate said organic solvent therethroughand thereabout; discharge the cellulosic solids fraction through anoutlet provided therefor approximate the second end; and discharge thefirst liquid fraction through an outlet provided therefor approximatethe first end.
 9. A modular system according to claim 1, wherein thefirst processing module is additionally provided with equipmentconfigured to sequentially saturate and de-saturate the processedlignocellulosic feedstock prior to physico-chemically digesting saidprocessed lignocellulosic feedstock.
 10. A modular system according toclaim 1, wherein the second processing module comprises a plurality ofequipment selected and configured for controllable and manipulablecommunication and cooperation for: receiving therein the cellulosicsolids fraction discharged from the first processing module; reducingthe viscosity of the cellulosic solids fraction; enzymatic digestion ofthe reduced-viscosity cellulosic fraction thereby producing a secondliquid fraction; fermentation of the second liquid fraction therebyproducing a beer therefrom; distillation of the beer thereby producing afuel-grade ethanol and a second stillage therefrom; and separating afirst class of lignin derivatives from said second stillage.
 11. Amodular system according to claim 1, wherein the de-lignified secondstillage is recyclable for reducing the viscosity of the cellulosicsolids fraction.
 12. A modular system according to claim 1, wherein thesecond processing module is provided with a vessel for containingtherein concurrent enzymatic digestion of the reduced-viscositycellulosic solids fraction and fermentation of the second liquidfraction produced therefrom.
 13. A modular system according to claim 1,wherein the anaerobic digestion module is provided with a plurality ofequipment configured for: receiving and biologically hydrolyzing thereinthe solid waste material separated by the fourth processing modulethereby producing a third liquid fraction; receiving and biologicallyacidifying therein the third liquid fraction thereby producing abiologically acidified liquid fraction; receiving and biologicallyacetifying therein the biologically acidified liquid fraction therebyproducing at least acetic acid; and receiving the at least acetic acidand biologically producing at least a biogas and a liquid effluenttherefrom.
 14. A modular system according to claim 13, wherein theanaerobic digestion module is additionally configured for controllablyreceiving and commingling a portion of said sugar syrup separated in thefourth processing module with the a third liquid fraction.
 15. A modularsystem according to claim 1, additionally provided with a sixthprocessing module configured for receiving, fermenting and distillingtherein said sugar syrup, and for separating therefrom a distillate anda stillage.
 16. A modular system according to claim 15, wherein saiddistillate comprises at least 1,3 propanediol.
 17. A modular systemaccording to claim 15, wherein said distillate comprises at least lacticacid.
 18. A modular system according to claim 1, wherein a portion ofthe sugar syrup separated in the fourth processing module iscontrollably delivered into the second module for production therein ofethanol therefrom.
 19. A modular system according to claim 1, whereinthe ethanol is a fuel-grade ethanol.
 20. A modular system forfractionation of lignocellulosic feedstocks into component parts andfurther processing of said component parts to recover ethanol therefrom,the modular process comprising: a first processing module configured forfractionating a lignocellulose feedstock into component parts with anorganic solvent separately provided thereto and separating saidcomponent parts into a first liquid fraction and a cellulosic solidsfraction; a second processing module configured for receiving thereinsaid cellulosic solids fraction and for producing therefrom ethanol anda first stillage; a third processing module configured for receivingtherein the first liquid fraction and separating therefrom at least saidorganic solvent and a second stillage; and a fourth processing moduleconfigured for separating the second stillage into at least a sugarsyrup and a semi-solid waste material, wherein a portion of the sugarsyrup separated in the fourth processing module is controllablydelivered into the second module for production therein of ethanoltherefrom.
 21. A modular system according to claim 20, wherein theethanol is a fuel-grade ethanol.
 22. A first class of lignin derivativesrecoverable from a lignocellulosic feedstock, said first class of ligninderivatives recoverable by a process comprising steps of: separating thelignocellulosic feedstock into a cellulosics solids fraction and aliquid fraction, and recovering therefrom the cellulosic solidsfraction; hydrolizing the cellulosic solids fraction thereby producing aliquid stream containing at least solubilized sugars; fermenting saidliquid stream thereby producing a fermentation beer; distilling saidbeer to produce ethanol and a stillage therefrom; and precipitating saidfirst class of lignin derivatives from said stillage; and recoveringsaid precipitated first class of lignin derivatives.
 23. A second classof lignin derivatives recoverable from a lignocellulosic feedstock, saidsecond class of lignin derivatives recoverable by a process comprisingsteps of: fractionating the lignocellulosic feedstock into a cellulosicssolids fraction comprising a first class of lignin derivatives and apressurized liquids fraction, and recovering therefrom the pressurizedliquids fraction; depressurizing and cooling the liquids fractionthereby precipitating therefrom a second class of lignin derivatives;and separating and recovering said precipitated second class of ligninderivatives from said de-pressurized and cooled liquids fraction.
 24. Athird class of lignin derivatives recoverable from a lignocellulosicfeedstock, said third class of lignin derivatives recoverable by aprocess comprising steps of: fractionating the lignocellulosic feedstockinto a cellulosics solids fraction comprising a first class of ligninderivatives and a pressurized liquids fraction, and recovering therefromthe pressurized liquids fraction; depressurizing and cooling the liquidsfraction thereby precipitating therefrom a second class of ligninderivatives; separating the precipitated second class of ligninderivatives from said de-pressurized and cooled liquids fraction therebyproducing a partially delignified liquids fraction; precipitating athird class of lignin derivatives from said partially delignifiedliquids fraction; and recovering the third class of lignin derivatives.